Hammer-crusher rotors are used, for example, for crushing, shredding, or breaking scrap metal, such as automobile frames and bodies or other metal scraps. The hammer-crusher rotor essentially comprises a strong shaft which is rotatably and drivably supported at both of its ends in a housing of the hammer-crusher. The housing further encloses an anvil or an anvil surface. The scrap metal is crushed or broken between the rotating, impacting hammers of the hammer-crusher rotor and the respective anvil surfaces. Furthermore, the housing comprises an intake opening for the scrap material to be crushed or shredded and an outlet for the crushed or shredded material. A plurality of disks is rotationally, rigidly arranged on the shaft of the hammer-crusher rotor, so that the disks rotate with the rotating shaft. Each of the disks may comprise a respective hub and a disk body, whereby the axial width of the disk body is less than the axial width of the hub so that annular spaces are formed between neighboring disks. Each disk comprises a plurality of through-going bored holes running in parallel to the shaft and arranged at a uniform spacing from one another along a divided or pitch circle at a spacing away from the disk center and near the outer circumference of the disk body. The through-going bored holes of all the disks of the hammer-crusher rotor are aligned in a direction parallel to the lengthwise axis of the hammer-crusher rotor. An axle rod is passed through each respective set of aligning or bored holes to pass through all of the rotor disks. Thus, the arrangement is such, that the number of axle rods corresponds to the number of holes in each disk and that these rods are arranged eccentrically about and parallel to the shaft of the hammer-crusher rotor. The individual axle rods may respectively be rigidly held in end disks of the hammer-crusher rotor. According to a determined pattern, the number of hammers arranged to freely rotate on each axle rod may vary from rod to rod. The hammers each have an axial width or thickness so that they fit into the space between adjacent disk bodies, whereby during rotation of the rotor, the hammers can freely rotate about the axle rod in a segment of the circular space between two neighboring disk bodies.
When the hammer-crusher rotor is used for crushing or shredding metal scraps the parts of the hammer-crusher which come in direct contact with the scrap metal are subject to a very high wear. The wear is not only due to abrasion, for example of the disks, rather it frequently occurs that small parts or chips of the disk are chipped away so that the disks must be replaced or renewed at time intervals which may differ from disk to disk.
German Patent Publication (DE-PS) 2,605,751 discloses protective shields for hammer-crusher rotors, which are made of specially wear resistant material and which respectively comprise a circular ring segment shaped cover part and a corresponding bearing hub provided on the inner surface of the cover part. Each protective shield is arranged between two adjacent disks and is secured by its bearing hubs to a respective axle rod. The cover parts cover the circumferential surfaces of the respective adjacent disks so that all the protective shields together form an essentially closed protective shell or jacket, whereby the hammers protrude from slots in the jacket. It is the purpose of the essentially closed known protective shell or jacket to protect the outer surfaces of the rotor disks against wear. The known protective shell achieves its purpose. However, the known shell is assembled from several separate elements, namely the separate protective shields which are relatively costly and complicated due to their special shape and are therefore expensive to produce. The cover parts of the protective shields for the circumferential surfaces entail a high production cost which still does not avoid curvature errors. Any curvature errors will result in undesirable edge loading during operation of the known hammer-crusher rotor with a resulting danger of fracture or rupture.